Iron-cased induction-coil for alternating-current transfer



(No Model.)

. E. THOMSON. IRON CASED INDUCTION COIL FOR ALTERNATING CURRENT TRANSFER.

No. 414,266. Patented Nov. 5, 1889.

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ELIHU THOMSON, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THE THOMSON- HOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

IRON-CASED INDUCTION-COIL FOR ALTERNATING-CURRENT TRANSFER.

SPECIFICATION forming part of Letters Patent No. 414,266, dated November 5, 1889.

Application filed February 12, 1887. Serial No. 227,446. (No model.)

To all whom it may concern.-

Be it known that I, ELIHU THOMSON, acitizen of the United States, and a resident of Lynn, in the county of Essex and State of Massachusetts, have invented certain new and useful Iron-Cased Induction-Coils for Alternating-Current Transfer, of which the following is a specification.

My invention consists in disposing the wires of an induction-coil so as to bring the conductors of the primary and secondary coils into close proXimity L'. a, to make every wire or turn of the primary as near as practicable to all the turns of the secondary, and every single turn of the secondary as near as practicable to every turn of the primary coil. This is done by making the combined sections of the two coils, however wound, approximate a square or other equilateral or a circular figure, as' such figure has a maximum area included under minimum length of boundaries, and all parts therefore are as near together as practicable. The circular section would be the most perfect, but it is difficult to wind wire in such section, and a square gives ease of winding and almost as good effects in practice. A slightly-rectangular section would depart a little in effect from that of a square section.

Anotherimprovement consists in giving the combined primary and secondary coils of a square or circular or approximate transverse section a diameter such that the coils may inclose a large body of iron in the center and may be inclosed or incased in iron for the purpose of providing as complete as practicable a magnetic circuit around the coils. The mag netic casing goes all over and around the coils and is made, preferably, of soft iron divided into strips, sheets, or wires, the divisions always existing parallel to the direction of magnetic polarization and transverse to the direction of currents in the coils so as to cut off all flow of induced current in the casing of iron. 45 The minimum length of such casing or magnetic circuit around the coils is also secured by giving the said coils a circular or approximate section, a square section answering the purpose sufficiently well, as the wires are 50 massed closely together.

In the accompanying drawings, Figure 1 shows a square section-coil, the primary and secondary P and S being massed and placed in lateral juxtaposition. Fig. 2 shows a square section-coil with the primary and secondary superposed. Fig. 3 shows two primariesP P, with a secondary coil S between. In Fig. at the combined section of the coils P S is nearly round. Fig. 5 is a cross-section of a coilwith an iron envelope made of wire. Fig. 6 is a side elevation and section of the same. Fig. 7 is a side elevation of a modified form of envelope or casing. Fig. 8 is a cross-section. Fig. 9 is a modification-of theform shown in Figs. 7 and S.

Iwind the coils disposed as in Figs. 1, 2, 3, and 4:, with iron wire I I, Figs. 5 and 6, the wire passing through the axis and over the exterior, giving an iron casing covering the coils externally of the shortest length of magnetic circuit, and in which magnetic circuit reversals of magnetism take place during passage of alternating currents in the coil P, the result being the induction of very powerful currents in S, but little inferior in energy to the currents in the primary coil.

In Figs. 7 and 8 the casing is modified to facilitate construction and adjustment. A central core of sheet-iron or wire C has its magnetic circuit completed and intensified by end plates 1, slit from the center out so as to divide them at several points and prevent currents being set up in them, and the outer edges of the end plates are magnetically united by iron wires or by sheet-iron strips 1', connecting the outer edges of I, as shown. The plates 1 might be made continuous with I, and of sheet-iron stamped into the shape I, Fig. 9, and placed as shown with respect to the core C. This special construction forms the subject of another application.

The core C may be made movable in its length so as to vary the permeability or completeness of the magnetic circuit around coils P and S, and so vary their inductive effects.

\Vhat I claim as my invention is 1. The combination, with. an induction-coil having its primary and secondary conductors arranged as described, so that the cross-sectional figure will approach a square orother angular form whose sides are of substantially equal length, of an iron casing applied as shown and described, so as to have minimum magnetic resistance.

2. An induction-coil clad with iron inclosing both primary and secondary conductors, said primary and secondary coils together having a figure in cross-section which is substantiallya square with sides of substantially equal length,- as and for the purpose described.

3. The combination, with one or more electric coils, of U-shaped iron plates or pieces between whose legs the conductors of the coil lie, and yoke-pieces connecting the two legs, so as to complete a magnetic circuit around the circumferential axis of the coil.

'4. The combination, with one or more electric coils, of a magnetic envelope formed at the sides of the coil, of masses of iron subdi vided in lines transverse to the lineof the coils, but substantially parallel to the plane of winding, and alaminated mass of iron connecting the iron at the sides of the coil on the outer periphery thereof, as and for the purpose described.

Signed atLynn, in the county of Essex and State of Massachusetts, this 7th day of February, A. D. 1887.

ELIHU THOMSON.

Witnesses:

J. W. GIBBONEY, E. WILBUR RICE, Jr. 

